SAFE welding on a Diesel fuel tank??

Happy Monday out there,

Looking to weld a small tab on my Diesel tank so I can lock my cap. Since diesel is less volatile than gasoline I wonder if it's safe to do so?
I'll be MIG welding a spot near my cap, which is surface mounted to the tank.

Thanks!
John

 

If the tank is full of something, diesel or water, it'll be fairly safe.

It is when you get a bunch of fuel vapour and air that it becomes dangerous.

 

Empty it & Purge it with something like argon or exhaust from a running vehicle.
I don't care for water filled welding much .

 

I wouldn't do anything unless the tank was almost full of water, but what do I know. I probably still wouldn't take any chances.

 

Empty tank and purge it with inert gas.

 

I have welded them with stick rods.
Fill with diesel, extend neck with robber tubing, with wet rag on top, weld away.
Bruce

Works good
Lasts long time

 

Fill it right to the top with diesel. Seen it done lots.

 

this is the best way to weld on a tank . with water there is still a chance of a air pocket. i like the exhaust way the best...have welded a lot of tanks this way car and bike. i have a old hose off a gas pump that i shove it into a exhaust pipe use rags to jam it in start the car put the other end into the tank ur welding give it a min or two then weld while the car is running

 

That might work and then you could be the first stic welder on the moon

 

Don't do it ! If you don't believe me go on the internet and look up welding diesel tank,s . Purge it real good or better yet take it off and wash it out with soap and water. Then you will be safe .I have welded plenty of diesel and gas tank's but I would never ever do it without making perfectly certain it was clean.

 

Welded lots of diesel tanks both steel and aluminum, as said fill to the top. pour some diesel in a bowl and throw a match in it it will go out, unlike gas!

 

Years back in Texas there was a radiator shop down from the parts store I worked at. Used to see those guys welding on diesel tanks all the time. One time I was in there, one of the guys was welding up a hole in the side of a tank on a semi, fuel streaming out as he welded it up tight. Made me nervous as hell but they said with the low flash point there was no reason to panic and they did it all the time...

 

exhaust from a car or even a lawn mower works and when the tank gets warm, it's ready to weld

 

exhaust or argon, Ive heard of people using dry ice also.

 

Get someone to video the welding operation, just in case all the advice was wrong. They can post to this thread and no one else will make the same mistake.

 

Be aware that we are talking about diesel tanks, Not gas tanks, propane tanks, etc.
Bruce

Works good
Lasts long time

 

one little problem, diesel contains WAAAAAAY more BTU's so if it does ignite, it has way more force than gas vapor, and fyi you can put a match out in a bowl of gas too ya just have to waft the vapors away. I wouldn't touch it until it was purged...

 

I did it with a full tank of fuel and stick welded it when I was younger, now, I wouldn't do it. Smarter? Scared? Getting old?

 

Can be done...I've welded cracks on 3/16" thick locomotive tanks 1/2 full, purging with nitrogen

 

I've done it lots.....
But then what do I know....I'm just a dumb diesel mechanic.....
Sometimes it's just not feasible to remove a 200 gallon leaking diesel tank off a CAT out in the field......

The "best" way is to flush the tank....purge it....blah, blah.....that's the "safe" way....

 

Diesle will burn and quite well I might add.
Saw a jet car go up in flames at norwalk raceway back in the early 90s from a fuel leak with some on the track.
Saw a 10' diameter tank being cut in half and make one hell of a fire ball, 300' estimated height.
Saw a salimander heater get knocked over and cause one giant fire.
Seen aftermath of spaceheater leaks.
No fng way I'm Certainly not going to weld on it with fuel pouring out if it.

I can't imagine any type of tig welded aluminium with fuel oil oozing into the weld.


You want safe, drain it, purge it, and have at welding it, that way all risk of the fuel has been isolated or eliminated. If you want you could remove it, and wash it too. Better wash it if its had gasoline in it.

 

Take it to a good shop, they should have insurance if some thing goes wrong, or just look into a locking fuel cap.

 

It is the HIGH flash point that makes it safe, the lower the flash point the easier it is to ignite...but a weld is hot enough to catch diesel on fire, so keep an extinguisher handy... and purge the tank with a non flammable gas....you will NEVER get all the water out of it...

 

I'll go with the purge suggestions. I'd just buy a locking cap, but it's an Isuzu NPR tank with the fine thread 2" filler neck.

 

My weld would be a brief small weld. Just want to add a simple lock-tab over the cap to prevent theft.

 

Guys at the locomotive shop at work welded on (empty) fuel tanks quite often. If I remember, there was a 24hr steam purge rule.

 

The final theory on the explosion and crash of TWA flight 800 was that a spark ignited a fuel tank. Jet fuel is alot like diesel fuel.

 

I had askes a welding shop about welding on a large deziel tanker and they said that all you have to do is discharge a co2 fire extinguisher inside and your ok to weld.

Two weeks later they made the news paper.Guess why!

 

If I remember right the flash point of diesel is around 130. Think you will get it that hot welding?

I bet there have been hundreds of tanks that were welded with fuel in them. You want to be the statistic that burned up?

Now, I spent the entire afternoon drumming race gas in a warehouse in Lubbock when one of my drivers walked up smoking a cigarette and was mildy offended when I told him to go away. Flash point -37.

Be safe out there kids.

 

I have a friend who has welded diesel tanks for 20 years, about three years ago one popped out the side on him and he was almost burned to death. He lived but has limited use of one of his arms. He was burned over 80% of his body if I remember right. I do remember that I will never weld on a tank that has diesel in it EVER I dont care what kind of bullshit some guy feeds me about flashpoint and air pockets! do yourself a favor empty the tank and have it boiled out and then purge weld it with an inert gas. the life you save WILL BE YOUR OWN.